Answer
(a)
Increasing on $(-4, -1)\cup(0.5,2)\cup(2, 4)$,
Decreasing on $(-1,0.5).$
(b)
Absolute maximum at $(4,3)$.
No absolute minimum.
Local maximum at $(-1,2)$ and $(2, 1)$.
Local minimum at $(-4, -1)$ and $(0.5, -1)$.
Work Step by Step
See image below.